An engineer, a physicist and a mathematician are staying in a hotel one night, when a small fire breaks out in each of their bedrooms.
The physicist, waking to the smell of smoke, begins a long series of calculations based on the specific heat capacity of water, the latent heat of steam, the enthalpy of combustion and the ignition temperature of the furnishings; and then pours onto the fire the exact amount of water required in order to extinguish it, yet evaporate completely from the residual heat, leaving the minimal amount of damage.
The engineer, waking to the crackle of flames, locates the seat of the fire, the sink and a suitable container; then begins pouring water on the fire, a bucket at a time, until it is out; then throws on as much water again, just to create a margin of safety.
The mathematician, waking to a sudden increase in temperature, notices that there is a sink in the room; turns on the tap to check the rate at which water is coming out of it; then, satisfied that a solution exists, leaves the rest as an exercise for the reader.